[en] A circuit design used in long distance data collection system, for raising the reliability and resisting the interference by self-coding based on PC and chip microprocessors is introduced. The system is important to supervise the voltages and temperatures in the Shower Counter electronics system of BES

No abstract available

[en] In order to study the mechanism of chain scission and the racemization processes, the radiation effect on iso-polymethyl methacrylate in its various states was studied, i.e. amorphous solid, crystalline state and in solution. In solution, especially in dilute solution, the polymer chain and its segments are much more mobile than in their solid states. In their solid state, especially in crystalline state, the chains and their segments are restricted. This study is significant for the study of the mechanisms of radiation-induced chain-scission and racemization. (author)

[en] In this paper, effect of ethylene glycol dimethyacrylate (EGDMA) on radiation reactions of random 1,2-polybutadilene (1,2-PB) was researched. In order to get information on radiolytic changes in 1,2-PB, the Sol fraction, the converation of double bonds, the structure chang of the irradiated sample were measured by using IR and ¹H-NMR techniques. The results show that random chain process of crosslinking in irradiation is not changed by the presence of EGDMA in 1,2-PB, its G(c.1) and G(I) Value increases with increasing of the ratio of EGDMA to 1,2-PB in the system, while its G(-V) and G(cy) decreases with that. In presence paper, the mechanism of effect of EGDMA on radiation reactions of 1,2-PB was also discussed

[en] Short communications only

[en] Objective: To investigate the CT findings and clinical features of COVID-19 patients with different clinical subtypes. Methods: Retrospective analysis was performed on the clinical and the initial CT imaging data of 189 COVID-19 patients (91 males and 98 females, mean age 46.5 ± 16.6 years) from January 24 to February 17, 2020. They were divided into common group (common type, 153 cases) and severe group (severe or critical type, 36 cases). Chi-square test or t test was used to compare the clinical features and CT findings between the two groups. Results: The proportion of males (72.2%), age (55.9 ± 15.4 years), incidences of hypertension, diabetes, dizziness, headache, aches and pains, shortness of breath and high fever, and rate of abnormal leukocyte, lymphocyte and neutrophil were higher in the severe group than in the common group (all P < 0.05). The lesions involved bilateral lungs, more than 10 lung segments in all patients in the severe group. The number of lesions (24.8 ± 13.5 vs 12.3 ± 8.8) and rates of simple consolidation shadow and subpleural effusionin were higher in the severe group than in the common group (all P < 0.05). Conclusion: There are significant differences in clinical symptoms, laboratory examination and CT findings between patients with common COVID-19 and patients with severe/critical COVID-19. Understanding and mastering these differences is helpful for clinicians and radiologists in severity assessment of COVID-19 patients. (authors)

[en] The gamma-radiation effect on random 1,2-polybutadiene was studied by measureing sol fraction, double bonds conversion (by IR) etc.. The network formation of irradiated unsaturated polymer was analysed and discussed theoretically. For the random chain reaction of irradiation 1,2-PB, the relation between sol fraction S and radiation dose R/or crosslinking index γ/can be expressed as a logarithmic fuction. By solving the logarithmic equition, some information on crosslinking of irradiated unsaturated polymer system can be obtained. For the random 1,2-PB with high 1,2-unit contet, both intermolecular crosslinking and intramolecular cyclization take place simultaneously during irradiation, and cyclization reaction exceeds crosslinking formation G(cy) > G(c.l). The effect of molecular weight of irradiated sample on radiation crosslinking was also discussed

[en] The influences of irradiation on Positive Temperature Coefficient (PTC) functions of polymer-carbon black composites are studied systematically, using HDPE, LDPE, PE/EPDM, PE/EEA as polymer matrixes and carbon black as conductive fillers. The results show that under a certain radiation dose, a remarkable improvement of the PTC intensity and the reproducibility of PTC curves of most polymer blends can be achieved, and Negative Temperature Coefficient (NTC) effects are decreased or eliminated. The mechanism of crosslinking structure on improving and stabilizing the PTC functions of polymer blends is also discussed through modern structural analysis methods. In this paper, an interesting and significant phenomenon is discovered. The PTC curve of PE/EPDM/CB composite presents an obvious NTC phenomenon as the dose exceeding 2 MGy. (author)

[en] The seven kinds of elements are the main parts in core of the pulsed reactor, they are sealed up by welding. The welding technology, welding equipment and quality check are introduced. It is very successful that the elements are welded with the technologies of pulse-argon-arc-weld and helium-filling-point-weld

[en] Three types of polyacrylamide hydrogel were prepared by radiation techniques and their water retention values were determined. (author)